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VAIL – SIL - Safety Integrity Level

VAIL-SIL uses the Safety Integrity Level (SIL) method (VELOSI’s methodology for monitoring safety critical systems).

Process plant operate by using many sophisticated process control systems. These systems are required for the safe and reliable operation of the plant and address safety functions such as process sectioning, fire and gas detection, process protection and blow down. These safety functions are often designed by combining various E/E/PES technologies and other external risk-reducing devices. In addition, computer and software intensive systems are increasingly being used as part of the system.

Our solution

VAIL-SIL is a software product that uses the Safety Integrity Level (SIL) method as VELOSI’s methodology for monitoring safety critical systems. Safety Integrity Level (SIL) is a discrete level for specifying the safety integrity requirements of the safety functions to be allocated to the E/E/PE safety related systems. E/E/PES is a term introduced by the IEC61508 standard, which stands for Electrical, Electronics and Programmable Electronics Systems.

Various methodologies are available for the assessment of target SILs. VELOSI has implemented three different methodologies in our system:

  1. Layer of Protection Analysis (LOPA)
  2. Risk Matrix
  3. Risk Graph

Furthermore, VAIL-SIL is not limited to just calculating target SILs; among others, it also includes:

  • Overall summaries of SILs with mutual comparison of the three stated methodologies
  • Target PFD Calculations
  • Testing Interval Calculation
  • Mean Time Between Failure (MTBF),
  • Mean Time To Repair (MTTR),
  • Dynamic Reporting
  • SIL Study Session Team’s Record Management


By utilizing VELOSI’s SIL managing techniques and software, you can optimize the management of your safety critical systems and implemented protective functions in line with the industry’s best practices without compromising safety.

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